I have a 24X24 garage floor that was poured in September of 2003. A new garage has been built on it and as I was about to clean the floor I noticed cracks in the expansion joint that runs from the center of the slab toward the back. The floor was troweled into four sections and the crack extends from the front back to where the four points meet in the middle.
The cracks range in width of about 1/32 to maybe 1/8. I plan on filling them with something to prevent water entry, but my greater concern is should they be cracking already?
I live in Wisconsin. Temps havent been much lower than 20's for any real length of time, fwiw.